Lubricating oils are of key importance for society, economic growth and development, and maintenance of living standards. They play an irreplaceable role in transport, industry and all other areas that require flawless functioning of machines and equipment. This paper briefly presents all the key stages and ways in which lubricating oil affects the environment, human health, and plant and animal life. A detailed analysis of the use phase in which motor oil for lubrication burns in the internal combustion engine and thus contributes to the emission of toxic compounds through the exhaust systems of the vehicle was carried out. The use phase includes the leakage of motor oil from the oil sump of the vehicle, but also other applications of other types of lubricating oil such as those used in tools and machines throughout the industry. The influence of lubricating oil in the use phase on human health was analyzed, as well as the influence of waste lubricating oils on the entire ecosystem. A basic overview of technologies for the recovery of waste lubricating oils and examples of the regeneration process of the world's leading companies dealing with the recovery of this type of extremely valuable waste is also given. The oil recovery results in high quality base oils that are adequate for the production of new lubricating oils. Other technological processes used to process waste lubricating oil are also presented, and the mechanisms that contribute to the aging of lubricating oil and its accelerated degradation are also listed. In the final part of the paper, an overview of the management of waste lubricating oils in the Republic of Croatia is given.